Subgroup analysis of seizure and cognitive outcome after vagal nerve stimulator implantation in children.

OBJECTIVE: Vagal nerve stimulator (VNS) implantation at an early age seems to lead to improved quality of life and cognitive outcome. The aim of this analysis is to evaluate whether specific patient or seizure characteristics might lead to better seizure control, cognitive outcome, and higher quality of life in children undergoing VNS implantation. METHODS: Primary outcome measure was reduction in seizure frequency. Secondary outcome measures were epilepsy outcome assessed by McHugh and Engel classifications, reduction in antiepileptic drugs (AED), developmental and cognitive outcome, as well as quality of life assessed through the pediatric quality of life (PEDSQL™) questionnaire and care giver impression (CGI) scale. Forty-five consecutive children undergoing VNS implantation were analyzed for the following subgroups: age (categorized to 1-2 years old, 3-5 years old, 6-12 years old, and 13-18 years old), sex, underlying cause (categorized to idiopathic, encephalitis, stroke, syndromic), duration of preoperative seizures (dichotomized to under or above 89 months, corresponding to the median of the whole cohort), and preoperative seizure frequency (dichotomized to under and above 360 seizures per month). RESULTS: Encephalitis as the underlying cause for seizures was the only variable significantly associated with higher reduction rate of seizure frequency. Patients with VNS implantation at the age of ≤ 2 years showed a strong association with better developmental and cognitive outcome, as well as quality of life. Shorter duration of preoperative seizures and higher preoperative seizure frequency showed a strong association with better developmental outcome, as well as quality of life. Engel outcome scores were significantly better in patients with epilepsy due to encephalitis (100% Engel I-III). However, patients with epilepsy due to encephalitis showed significantly higher complication rates (71.4%, p = 0.045). CONCLUSIONS: Children suffering from epilepsy due to encephalitis show higher seizure reduction rates after VNS implantation when compared with children suffering from epilepsy due to other causes. Developmental and cognitive outcomes as well as quality of life of children undergoing VNS implantation is strongly associated with shorter duration of preoperative seizures and implantation at a young age.

Dual array EEG-fMRI: An approach for motion artifact suppression in EEG recorded simultaneously with fMRI.

OBJECTIVE: Although simultaneous recording of EEG and MRI has gained increasing popularity in recent years, the extent of its clinical use remains limited by various technical challenges. Motion interference is one of the major challenges in EEG-fMRI. Here we present an approach which reduces its impact with the aid of an MR compatible dual-array EEG (daEEG) in which the EEG itself is used both as a brain signal recorder and a motion sensor. METHODS: We implemented two arrays of EEG electrodes organized into two sets of nearly orthogonally intersecting wire bundles. The EEG was recorded using referential amplifiers inside a 3T MR-scanner. Virtual bipolar measurements were taken both along bundles (creating a small wire loop and therefore minimizing artifact) and across bundles (creating a large wire loop and therefore maximizing artifact). Independent component analysis (ICA) was applied. The resulting ICA components were classified into brain signal and noise using three criteria: 1) degree of two-dimensional spatial correlation between ICA coefficients along bundles and across bundles; 2) amplitude along bundles vs. across bundles; 3) correlation with ECG. The components which passed the criteria set were transformed back to the channel space. Motion artifact suppression and the ability to detect interictal epileptic spikes following daEEG and Optimal Basis Set (OBS) procedures were compared in 10 patients with epilepsy. RESULTS: The SNR achieved by daEEG was 11.05±3.10 and by OBS was 8.25±1.01 (p<0.00001). In 9 of 10 patients, more spikes were detected after daEEG than after OBS (p<0.05). SIGNIFICANCE: daEEG improves signal quality in EEG-fMRI recordings, expanding its clinical and research potential.

The Israeli retrospective multicenter open-label study evaluating vagus nerve stimulation efficacy in children and adults.

BACKGROUND: The management of intractable epilepsy in children and adults is challenging. For patients who do not respond to anti-epileptic drugs and are not suitable candidates for epilepsy surgery, vagal nerve stimulation (VNS) is a viable alternative for reducing seizure frequency. METHODS: In this retrospective multicenter open-label study we examined the efficacy and tolerability of VNS in patients in five adult and pediatric epilepsy centers in Israel. All patients had drug-resistant epilepsy and after VNS implantation in 2006-2007 were followed for a minimum of 18 months. Patients were divided into two age groups: < 21 and > 21 years old. RESULTS: Fifty-six adults and children had a stimulator implanted in 2006-2007. At 18 months post-VNS implantation, none of the patients was seizure-free, 24.3% reported a reduction in seizures of > or = 75%, 19% reported a 50-75% reduction, and 10.8% a 25-50% reduction. The best response rate occurred in patients with complex partial seizures. Among these patients, 7 reported a > or = 75% reduction, 5 patients a 50-75% reduction, 3 patients a 25-50% reduction, and 8 patients a < 25% reduction. A comparison of the two age groups showed that the older group (< 21 years old) had fewer seizures than the younger group. CONCLUSIONS: VNS is a relatively effective and safe palliative method for treating refractory epilepsy in both adults and children. It is an alternative treatment for patients with drug-resistant epilepsy, even after a relatively long disease duration, who are not candidates for localized epilepsy surgery.

Familial partial trisomy 15q11-13 presenting as intractable epilepsy in the child and schizophrenia in the mother.

Various rearrangements involve the proximal long arm of chromosome 15, including deletions, duplications, translocations, inversions and supernumerary marker chromosome of an inverted duplication. The large marker 15, that contains the Prader-Willi syndrome (PWS)/Angelman syndrome (AS) chromosome region, is usually associated with an abnormal phenotype of moderate to severe mental retardation, seizures, poor motor coordination, early-onset central hypotonia, autism and autistic-like behavior, schizophrenia and mild dysmorphic features. We report a ten year-old girl with normal intelligence prior to the onset of seizures, who developed severe intractable epilepsy at the age of seven years. Family history was significant for a mother with recurrent episodes of acute psychosis. The patient's and mother's karyotype revealed 47,XX+m. Array comparative genomic hybridization (A-CGH) identified a gain of 13 BAC clones from 15q11.2 through 15q13.1, which was then confirmed by FISH to be part of the marker chromosome. This duplicated region contains the SNRPN/UBE3A locus. This case demonstrates that a duplication of 15q11-13 can present differently in the same family either as intractable epilepsy or as a psychiatric illness and that intelligence can be preserved. We suggest that CGH microarray should be performed in cases with intractable epilepsy or schizophrenia, with or without mental retardation.